1. Field of the Invention
The present invention relates to a method for manufacturing a light-emitting device that provides a periodic structure along a direction to which the light is emitted.
2. Relater Prior Art
A laser diode with a distributed feedback structure has been well known as a DFB laser diode. To form the distributed feedback structure, a periodic undulation is induced in an active layer by dry-etching the active layer after the planar growth thereof. A Japanese Patent Application published as JP-2004-055797A has disclosed such manufacturing process for the DFB laser diode.
However, the dry-etching for the active region may induce plasma damage in the active region, which causes dislocations and defects to degrade the efficiency for emitting light due to non-radiative recombination centers brought by such imperfections in the lattice. Thus the threshold current of the laser diode increases.